The simultaneous display of several time measurable quantities is a prized complication in high-end watchmaking. However, it is difficult to ensure the safety of display mechanisms when the correction mechanisms are being operated. The action of the correction mechanisms may interfere with an operation of driving one of said display mechanisms, during a preparatory phase for said driving operation or during the actual driving operation. For example, correction of the date or time as midnight approaches is generally prohibited, or at least not recommended. The problem is particularly acute when several display mechanisms coexist. Some safety devices properly manage correction operations carried out in a dedicated position of the stem, but there is still a risk when the user envisages performing corrections, in particular in the direction opposite to normal operation, via the time-setting motion work.
CH Patent Application No. 394 959 A in the name of TAVANNES discloses a self-winding watch, with a manual winding and time-setting device and a date mechanism, comprising a lever pivoting about the axis of the crown wheel, and carrying an intermediate wheel constantly meshed with said wheel. This lever is controlled by a pull-out piece hinged to the winding stem so that it can occupy three positions: one where the intermediate wheel is inactive, another where it is meshed with the date-setting mechanism and another where it is meshed with the motion work. The crown wheel is constantly meshed with the winding mechanism. The lever carries a stud on which the intermediate time-setting wheel is fitted, the latter being friction fitted onto a shoulder of a drive cam of the date mechanism. A friction spring holds the intermediate wheel and cam assembled to each other. Depending upon the position of the pull-out piece and the lever, the trajectory of the cam intersects the trajectory of the teeth of the date disc so that the cam drives the date disc by a value slightly less than one step of its toothing, with a jumper spring performing the additional rotation.
DE Utility Model No. 86 10 798 U1 in the name of SCHWARTZ discloses a moon phase and tide indicator device, wherein the moon phase wheel is actuated by one tooth of an actuator lever returned by a jumper spring. This actuator lever is coupled to a first arm of a control lever, the other arm of which cooperates with a pin carried by a cam, which can be uncoupled from another pin carried by a control wheel, which pivots about the same axis as said cam.
CH Patent No. 589 880 B5 in the name of SSIH discloses a watch control mechanism with two calendar members, the date and the day of the week, which includes a single correction lever pivoting in a push manner fit on an arbour integral with the intermediate time-setting wheel, said arbour is engaged in an oblong hole of a bar in a position determined by the pinion lever sliding against a spring, the correction lever carrying a pivotally mounted corrector wheel set, which is permanently meshed with the intermediate wheel and alternately with one of the two calendar members.